National Council of Teachers of Mathematics. (1926). Yearbook. National Council of Teachers of Mathematics.
Chicago-Zitierstil (17. Ausg.)National Council of Teachers of Mathematics. Yearbook. [Place of publication not identified]: National Council of Teachers of Mathematics, 1926.
MLA-Zitierstil (9. Ausg.)National Council of Teachers of Mathematics. Yearbook. National Council of Teachers of Mathematics, 1926.
Achtung: Diese Zitate sind unter Umständen nicht zu 100% korrekt.